Download (3249Kb) - D-Scholarship@Pitt - University of Pittsburgh

MHz): δ 172.7, 171.4, 137.0, 136.4, 135.1, 130.9, 130.4, 128.4, 128.1, 128.0, 127.8, 126.8,
125.7, 121.9, 69.0, 52.5, 40.4, 36.9, 34.7, 21.4, 13.6; IR (thin film): ν 2950, 1736, 1637, 1446,
1350, 1223 cm -1 ; MS m/z (%) 389 (38), 358 (15), 330 (42), 298 (42), 105 (100); EI-HRMS calcd
for C25H27NO3 [M] + , m/z 389.1991 found 389.1984.
N
Bz
MeO2C Bn
211
1-Benzoyl-2-benzyl-4-ethylidene-2,3,4,5-tetrahydro-1H-azepine-2-carboxylic acid methyl
ester (211). Prepared by following general procedure M using: 75b (0.12 g, 0.32 mmol). First
portion of [Rh(CO)2Cl]2 (6 mg, 15 µmol) was added at 70 °C. After 2 h at 90 °C another portion
of [Rh(CO)2Cl] (6 mg, 15 µmol) was added and the reaction was heated to 90 °C for additional 2
h. Upon completion, the reaction mixture was filtered through a plug of silica gel to afford 211
(80 mg, 66%) as a mixture of E and Z olefin isomers in ratio of ~2.5 : 1. The isomers were
separated by semi-preparative HPLC (hexanes-EtOAc, 24 : 1, v/v, flow rate 3 mL/min, UV
detector at 254 nm) and assigned by nOe spectroscopy.
N
Bz
MeO2C Bn
1%
H
H
H
2.9%
CH 3
0%
N
Bz
MeO2C Bn
H H
major 211a minor 211b
N
Bz
MeO2C Bn
211a
CH 3
H
1.8% 0%
(Z)-211a: (major isomer – Rt = 35 min): 1 H NMR (CDCl3, 300MHz): δ 7.55-7.51 (m, 2H),
7.42-7.34 (m, 3H), 7.26-7.16 (m, 5H), 5.44 (q, J = 7.0 Hz, 1H), 5.13 (dd, J = 7.7, 2.5 Hz, 1H),
232